Fix isql bug #910430.
Add SET HEADING ON/OFF option
Add -M2 command-line option to send output of statistics and plans to the same file than the rest of the output.
Those items do not appear when using HELP SET inside isql or with isql -? from the command line.
o use predefined macros to test for sys/wait.h, time.h and sys/time.h
o search strcasecmp in libresolv only if strcasecmp and stricmp are not in libc
o use predefined macro AC_SYS_LARGEFILE to determine 64Bit I/O
o determine the alignment of long and double (ALIGNMENT,DOUBLE_ALIGN),
still need to write a test for FB_ALIGN!